Data hierarchy

From Wikipedia, the free encyclopedia

Data Hierarchy refers to the systematic organisation of data, often in a hierarchical form. Data organisation involves fields, records, files and so on.

A data field holds a single fact. Consider a date field, e.g. 19 September 2004. This can be treated as a single date field (eg birthdate), or 3 fields, namely, day of month, month and year.

A record is a collection of related fields. An Employee record may contain a name field(s), address fields, birthdate field and so on.

A file is a collection of related records. If there are 100 employees, then each employee would have a record (e.g. called Employee Personal Details record) and the collection of 100 such records would constitute a file (in this case, called Employee Personal Details file).

Files are integrated into a database. This is done using a Database Management System. If there are other facets of employee data that we wish to capture, then other files such as Employee Training History file and Employee Work History file could be created as well.

The above is a view of data seen by a computer user.

The above structure can be seen in the hierarchical model, which is one way to organise data in a database.

In terms of data storage, data fields are made of bytes and these in turn are made up of bits.